The best thing I can suggest is to use a wire of similar gauge - it doesn't have to be Pioneer-specific wire, just get any ol' wire in there. Beyond that, I can't provide any other technical support regarding the modification or repair of your headphones, sorry.
Had my HDJ-2000's a while now and love them! but unfortunately i lost sound from the right side a while ago and I'm well out of my warranty. Tried finding somewhere to repair them but it all came back with the same answers, and that is the cost of repair would be very steep for what the problem was; which I found out was the wiring.
I think, mainly, from over use, the wiring for the right can got frayed and then broke. Being out of warranty anyway, I've opened them up and the wiring was broke in a few places so all needs repairing. It is my last chance to get them back without having to pay £260 for a new pair.
All I'm really wanting to know is if anyone knows where i can buy this cable that's good quality to replace the old; or even better, if Pioneer could be so kind as to put me onto the same cable used!
Thanks for the help in advance guys!